from ryu.base import app_manager
from ryu.controller import ofp_event
from ryu.controller.handler import CONFIG_DISPATCHER, MAIN_DISPATCHER
from ryu.controller.handler import set_ev_cls
from ryu.ofproto import ofproto_v1_3
from ryu.lib.packet import packet
from ryu.lib.packet import ethernet
from ryu.lib.packet import vlan
from ryu.lib.packet import ether_types


class VLanTest(app_manager.RyuApp):
	OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION]

	def __init__(self, *args, **kwargs):
		super(VLanTest, self).__init__(*args, **kwargs)
		# define MAC address table
		self.mac_to_port = {}

	@set_ev_cls(ofp_event.EventOFPSwitchFeatures, CONFIG_DISPATCHER)
	def switch_features_handler(self, ev):
		# datapath == the OpenFlow switch that issued this message
		datapath = ev.msg.datapath
		ofproto = datapath.ofproto
		parser = datapath.ofproto_parser

		# push vlan tag, default ethertype is 802.1Q
		# vlan_vid: 4bit(control) | 12bit(value)
		actions = [parser.OFPActionPushVlan(),
				   parser.OFPActionSetField(vlan_vid=(0x1000 | datapath.id)),
				   parser.OFPActionOutput(ofproto.OFPP_CONTROLLER,
                                          ofproto.OFPCML_NO_BUFFER)]
		# only packets without a VLAN tag
		notag = parser.OFPMatch(vlan_vid=0x0000)
		self.add_flow(datapath, 1, notag, actions)

		# only packets with a VLAN tag
		hastag = parser.OFPMatch(vlan_vid=(0x1000, 0x1000))
		actions = [parser.OFPActionPopVlan(),
				   parser.OFPActionOutput(ofproto.OFPP_CONTROLLER,
                                          ofproto.OFPCML_NO_BUFFER)]
		self.add_flow(datapath, 1, hastag, actions)

		# default table-miss flow entry
		actions = [parser.OFPActionOutput(ofproto.OFPP_CONTROLLER,
                                          ofproto.OFPCML_NO_BUFFER)]
		self.add_flow(datapath, 0, parser.OFPMatch(), actions)

	def add_flow(self, datapath, priority, match, actions, buffer_id=None):
		ofproto = datapath.ofproto
		parser = datapath.ofproto_parser

		# immediately use the specified action
		inst = [parser.OFPInstructionActions(ofproto.OFPIT_APPLY_ACTIONS,
                                             actions)]
		if buffer_id:
			mod = parser.OFPFlowMod(datapath=datapath, buffer_id=buffer_id,
                                    priority=priority, match=match,
                                    instructions=inst)
		else:
			mod = parser.OFPFlowMod(datapath=datapath, priority=priority,
                                    match=match, instructions=inst)
		datapath.send_msg(mod)

	@set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
	def _packet_in_handler(self, ev):
		# If you hit this you might want to increase
		# the "miss_send_length" of your switch
		if ev.msg.msg_len < ev.msg.total_len:
			self.logger.debug("packet truncated: only %s of %s bytes",
                              ev.msg.msg_len, ev.msg.total_len)
		msg = ev.msg
		datapath = msg.datapath
		ofproto = datapath.ofproto
		parser = datapath.ofproto_parser
		in_port = msg.match['in_port']

		pkt = packet.Packet(msg.data)
		eth = pkt.get_protocols(ethernet.ethernet)[0]

		if eth.ethertype == ether_types.ETH_TYPE_LLDP:
			# ignore lldp packet
			return
		dst = eth.dst
		src = eth.src

		# vlan test
		vls = pkt.get_protocols(vlan.vlan)
		vids = map(lambda e: e.vid, vls)
		self.logger.info("vids %s", vids)

		# switch id
		dpid = datapath.id
		self.mac_to_port.setdefault(dpid, {})

		self.logger.info("packet in [%s:%s] %s --> %s", dpid, in_port, src, dst)

		# learn a mac address to avoid FLOOD next time.
		self.mac_to_port[dpid][src] = in_port

		if dst in self.mac_to_port[dpid]:
			out_port = self.mac_to_port[dpid][dst]
		else:
			out_port = ofproto.OFPP_FLOOD

		actions = [parser.OFPActionOutput(out_port)]

		# install a flow to avoid packet_in next time
		if out_port != ofproto.OFPP_FLOOD:
			match = parser.OFPMatch(in_port=in_port, eth_dst=dst)
			# verify if we have a valid buffer_id, if yes avoid to send both
			# flow_mod & packet_out
			if msg.buffer_id != ofproto.OFP_NO_BUFFER:
				self.add_flow(datapath, 20, match, actions, msg.buffer_id)
				return
			else:
				self.add_flow(datapath, 20, match, actions)
		data = None
		if msg.buffer_id == ofproto.OFP_NO_BUFFER:
			data = msg.data

		out = parser.OFPPacketOut(datapath=datapath, buffer_id=msg.buffer_id,
                                  in_port=in_port, actions=actions, data=data)
		datapath.send_msg(out)
